Police are asking people to avoid the area if possible or seek alternate routes.

"Enforcement action will also be taken if demonstrators illegally impede traffic in the roadway or attempt to shut down a freeway. The safety of our officers and citizens is the primary concern as individuals or groups gather to express their first amendment rights," a Dallas police news release said.

Dallas police have officers specially trained for riot patrol. Police say they will use buses and other heavy vehicles to form a barricade around City Hall. It will keep trucks and cars from getting near the crowds.